package com.kingbase.lucene.commons.analyzer.chinese.ik;
 
import java.io.IOException;
 
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.wltea.analyzer.core.IKSegmenter;
import org.wltea.analyzer.core.Lexeme;
 
public class IKTokenizer5x extends Tokenizer{
 
    //IK分词器实现
    private IKSegmenter _IKImplement;
     
    //词元文本属性
    private final CharTermAttribute termAtt;
    //词元位移属性
    private final OffsetAttribute offsetAtt;
    //词元分类属性（该属性分类参考org.wltea.analyzer.core.Lexeme中的分类常量）
    private final TypeAttribute typeAtt;
    //记录最后一个词元的结束位置
    private int endPosition;
     
     
    /**
    public IKTokenizer(Reader in , boolean useSmart){
        super(in);
        offsetAtt = addAttribute(OffsetAttribute.class);
        termAtt = addAttribute(CharTermAttribute.class);
        typeAtt = addAttribute(TypeAttribute.class);
        _IKImplement = new IKSegmenter(input , useSmart);
    }**/
     
    /**
     * Lucene 5.x Tokenizer适配器类构造函数
     * 实现最新的Tokenizer接口
     * @param useSmart
     */
    public IKTokenizer5x(boolean useSmart){
        super();
        offsetAtt = addAttribute(OffsetAttribute.class);
        termAtt = addAttribute(CharTermAttribute.class);
        typeAtt = addAttribute(TypeAttribute.class);
        _IKImplement = new IKSegmenter(input , useSmart);
    }
 
    /* (non-Javadoc)
     * @see org.apache.lucene.analysis.TokenStream#incrementToken()
     */
    @Override
    public boolean incrementToken() throws IOException {
        //清除所有的词元属性
        clearAttributes();
        Lexeme nextLexeme = _IKImplement.next();
        if(nextLexeme != null){
            //将Lexeme转成Attributes
            //设置词元文本
            termAtt.append(nextLexeme.getLexemeText());
            //设置词元长度
            termAtt.setLength(nextLexeme.getLength());
            //设置词元位移
            offsetAtt.setOffset(nextLexeme.getBeginPosition(), nextLexeme.getEndPosition());
            //记录分词的最后位置
            endPosition = nextLexeme.getEndPosition();
            //记录词元分类
            typeAtt.setType(nextLexeme.getLexemeTypeString());          
            //返会true告知还有下个词元
            return true;
        }
        //返会false告知词元输出完毕
        return false;
    }
     
    /*
     * (non-Javadoc)
     * @see org.apache.lucene.analysis.Tokenizer#reset(java.io.Reader)
     */
    @Override
    public void reset() throws IOException {
        super.reset();
        _IKImplement.reset(input);
    }   
     
    @Override
    public final void end() {
        // set final offset
        int finalOffset = correctOffset(this.endPosition);
        offsetAtt.setOffset(finalOffset, finalOffset);
    }
}